Method for manufacturing an organic semiconductor element

ABSTRACT

In manufacturing a device using an organic TFT, it is essential to develop an element in which a channel length is short or a channel width is narrow to downsize a device. Based on the above, it is an object of the present invention to provide an organic TFT in which characteristic is improved. In view of the foregoing problem, one feature of the present invention is that an element is baked after an organic semiconductor film is deposited. More specifically, one feature of the present invention is that the organic semiconductor film is heated under atmospheric pressure or under reduced pressure. Moreover, a baking process may be carried out in an inert gas atmosphere.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic semiconductor element havingan organic semiconductor film and a method for manufacturing thereof.

2. Description of the Related Art

In recent years, a display device provided with a thin film transistor(hereinafter, a TFT) having a thin film semiconductor has been studiedand put into practical use. A high-resolution display device can beachieved since a large number of pixels can be constituted in thedisplay device provided with a TFT. Moreover, the display deviceprovided with a TFT can be operated in low power consumption comparedwith a CRT. Furthermore, the display device provided with a TFT occupiessmall space, since a display can be made without using a large-sizeddisplay tube like a CRT. Thus, the display device provided with a TFThas been widely used for a display portion of a personal computer, aPDA, a TV, or the like.

A display device which is made thinner, lighter, and more flexible isrequired in future. However, most of conventional TFTs have beenmanufactured by using an inorganic semiconductor material such asamorphous silicon or crystalline silicon as a semiconductor film.Therefore, the use of a resin substrate such as a plastic is limitedsince a processing temperature of 350° C. or more is required forforming a semiconductor film in the case where a TFT is formed by usingan inorganic semiconductor material.

In recent years, an organic thin film transistor (hereinafter, anorganic TFT) in which an organic semiconductor is used as asemiconductor layer has been studied. An organic TFT has highflexibility since an organic material is used. Moreover, a device usingan organic semiconductor can be manufactured at a lower temperaturecompared with a device using an inorganic semiconductor; thereby a resinmaterial such as a plastic can be used for a substrate. As a result, alightweight and flexible device can be obtained.

Moreover, as for an organic TFT, it is expected that not only canprocess such as a printing method, an ink-jetting method, and a vapordeposition method be simplified, but a manufacturing cost of a devicecan be also suppressed since an inexpensive material for a substrate canbe used, and thus it is advantageous in view of the cost.

Moreover, as for an organic TFT manufactured at present, a TFT elementin which pentacene is laminated over an SiO₂/Si substrate in which onlysurface cleaning is carried out and over a substrate in which thesurface is treated with HMDS after carrying out surface cleaning underthe same condition is manufactured. (refer to Non-Patent Document 1: I.Yagi, K. Tsukagoshi, and Y. Aoyagi, “Pentacene FET fabricated on surfacetreated SiO₂/Si substrate”, Proceedings of the 50^(th) Japan Society ofApplied Physics Lectures (March 2003), lower section of p. 1418.)

According to the Non-Patent Document 1, as for an organic TFT in which asurface is not treated, preferable TFT characteristic can be obtained inmobility, ON-OFF ratio, or a threshold value only in the case of usingan element in which a channel length is long or a channel width is wide.

However, in the case of manufacturing a device using an organic TFT, itis essential to develop an element in which a channel length is short ora channel width is narrow in order to downsize a device.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an organic TFT inwhich characteristic is improved by a method which is different from theabove-mentioned Non-Patent Document 1.

Moreover, an organic semiconductor has a disadvantage in which anorganic semiconductor is deteriorated due to moisture or atmospheric airin the case of being left in atmospheric air; and thus TFTcharacteristic is decreased. Furthermore, characteristic of an organicsemiconductor element is influenced by the adhesion strength between anorganic semiconductor film and an electrode, and between the organicsemiconductor film and an insulating film.

In view of the foregoing problems, it is an object of the invention toprovide a method for manufacturing an organic semiconductor elementwhich can prevent TFT characteristic from deteriorating even if anelement in which a channel length is short or a channel width is narrow.

One feature of the invention is that an element is heated (also referredto as “baked”) after an organic semiconductor film is deposited.

One feature of a specific method for manufacturing an organicsemiconductor element according to the invention includes the steps offorming an organic semiconductor film, and then heating the organicsemiconductor film under atmospheric pressure or under reduced pressure.

One feature of a method for manufacturing an organic semiconductorelement according to the invention includes the steps of forming a gateelectrode, forming an organic semiconductor film over the gateelectrode, then heating the organic semiconductor film under atmosphericpressure or under reduced pressure, and then forming a source electrodeand a drain electrode over the heated organic semiconductor film.

One feature of a method for manufacturing an organic semiconductorelement according to the invention includes the steps of forming a gateelectrode, forming a source electrode and a drain electrode over thegate electrode, then forming an organic semiconductor film over thesource electrode and the drain electrode, and then heating the organicsemiconductor film under atmospheric pressure or under reduced pressure.

One feature of a method for manufacturing an organic semiconductorelement according to the invention includes the steps of forming anorganic semiconductor film to be in contact with an inorganic film, andthen heating the organic semiconductor film under atmospheric pressureor under reduced pressure.

One feature of a method for manufacturing an organic semiconductorelement according to the invention includes the steps of forming anorganic semiconductor film to be in contact with a gate insulating film,and then heating the organic semiconductor film under atmosphericpressure or under reduced pressure.

According to the invention, an organic semiconductor film may be heatedat a temperature which is less than the melting point of an organicsemiconductor film material.

According to the invention, an organic semiconductor film may be heatedat a temperature which is less than 250° C.

According to the invention, an organic semiconductor film may be heatedat a temperature in which average value of the grain boundary (grain)size of the organic semiconductor film does not grow 10% or more.

As for the organic semiconductor element formed in the above-mentionedmanner, a substrate formed by synthetic resin such as a plastic, anacryl or the like typified by polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyethersulfone (PES) can be used sinceheating temperature is low in manufacturing process.

The baking may be carried out either under atmospheric pressure or underreduced pressure; however, the baking temperature can be lowered underreduced pressure. Accordingly, it can be expected that the deteriorationof the organic semiconductor element due to heating is reduced.Especially, the baking is preferably carried out at a low temperature inthe case where synthetic resin is used for the substrate. Moreover, thebaking may be carried out in an inert gas atmosphere.

The gate electrode, or the source electrode and the drain electrode canbe formed by using a sputtering method, an ink-jetting method, a spincoating method, or a vapor deposition method. In addition, the gateelectrode, or the source electrode and the drain electrode can be formedby an element selected from the group consisting of W, Ta, Ti, Mo, Al,and Cu; or an alloy material or a compound material in which at leastone of the elements is used as a main component.

Furthermore, the organic semiconductor element formed in theabove-mentioned manner can be obtained and the organic semiconductorelement can be provided for a pixel portion of a liquid crystal displaydevice or a display device having a light emitting element to use as asemiconductor element according to the invention. Especially,flexibility and lightweight of the liquid crystal display device or thedisplay device having a light emitting element can be enhanced byproviding the organic semiconductor element over synthetic resin.

According to the invention, a threshold value of ON-OFF can be changedand leakage current at OFF state can be reduced. Thus, the thresholdvalue of ON-OFF can be made close to 0V to raise ON-OFF ratio.Accordingly, characteristic of the organic semiconductor element can beimproved.

Moreover, due to the improvement, practicable TFT characteristic can beobtained even if an element in which a channel length is short and achannel width is narrow is used, and thus a device such as a displaydevice can be downsized.

These and other objects, features and advantages of the invention willbecome more apparent upon reading of the following detailed descriptionalong with the accompanied drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an organic thin film transistor ofbottom contact type according to the present invention;

FIG. 2 is a cross-sectional view of an organic thin film transistor oftop contact type according to the invention;

FIG. 3 shows a diagram showing an arrangement of an electrode accordingto the invention;

FIG. 4 shows a graph showing an experimental result according to theinvention;

FIG. 5 shows a graph showing an experimental result according to theinvention;

FIG. 6 shows a graph showing an experimental result according to theinvention;

FIG. 7 shows a graph showing an experimental result according to theinvention;

FIG. 8 shows a graph showing an experimental result according to theinvention;

FIG. 9 shows an AFM view showing an experimental result according to theinvention;

FIG. 10 shows an AFM view showing an experimental result according tothe invention;

FIG. 11 is a top view of a liquid crystal device including asemiconductor device according to the invention;

FIGS. 12A and 12B are cross-sectional views of a liquid crystal deviceincluding a semiconductor device according to the invention; and

FIGS. 13A to 13C are views of electric appliances and the like to whichthe invention is applied.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, embodiment modes according to the present invention will bedescribed in detail with reference to the drawings. However, the presentinvention can be carried out in many different modes, and it is easilyunderstood by those who are skilled in the art that embodiments anddetails herein disclosed can be modified in various ways withoutdeparting from the purpose and the scope of the present invention.Therefore, it should be noted that the description of the embodimentmodes to be given below should not be interpreted as being limited tothe present invention. Further, in all of views for describing theembodiment modes, the similar portion or the portion which have thesimilar function is marked with the same reference number, and arepeated explanation thereof will be omitted.

Embodiment Mode 1

In this embodiment mode, a method for manufacturing an organic TFT isdescribed as an organic semiconductor element of bottom contact type.

FIG. 1 shows a cross-sectional view of an organic TFT of bottom contacttype. The organic TFT of bottom contact type has an element structure inwhich an organic semiconductor film is formed after a source electrodeand a drain electrode are formed.

First, a conductive film (hereinafter, a gate electrode) 101 whichserves as a gate electrode is formed over a substrate 100 having aninsulating surface. Note that a method for manufacturing an organic TFTin this embodiment mode is illustrated with an example in which a quartzsubstrate is used for the substrate 100 having an insulating surface,tungsten (W) is used as the conductive film 101 over the quartzsubstrate, and the gate electrode is formed by a sputtering method, butthe present invention is not limited to this.

As a substrate having an insulating surface, a glass substrate such as abarium borosilicate glass and an alumino borosilicate glass, or astainless steel substrate or the like can be used. Moreover, it ispreferable to use a substrate formed by synthetic resin such as aplastic or an acryl typified by polyethylene terephthalate (PET),polyethylene naphthalate (PEN), polyethersulfone (PES). A substrateformed by such synthetic resin is flexible and lightweight.

Moreover, a substrate is preferably used after polishing the surface bya chemical or mechanical polishing method, so called CMP(Chemical-Mechanical Polishing), to enhance planarity of the substrate.As a polishing agent (slurry) of CMP, a polishing agent in which fumedsilica particles obtained by pyrolyzing a chloride silicon gas aredispersed into a KOH solution can be used.

If necessary, a base film may be formed over the substrate. The basefilm serves as to prevent an alkaline metal such as Na or an alkalineearth metal included in the substrate from dispersing into asemiconductor film; therefore, adverse effect on the characteristic of asemiconductor element is prevented. Therefore, the base film can beformed by using an insulating film such as silicon oxide, siliconnitride, silicon nitride oxide, titanium oxide, and titanium nitridewhich can prevent an alkaline metal or an alkaline earth metal fromdispersing into the semiconductor film.

The gate electrode may be formed by an element selected from the groupconsisting of Ta, Ti, Mo, Al, and Cu; or an alloy material or a compoundmaterial in which at least one of the elements is used as a maincomponent, in addition to tungsten. Moreover, the gate electrode canhave a single layer structure or a laminated structure. Furthermore, thegate electrode may be formed by using a screen printing method, a rollcoating method, a droplet discharge method, a spin coating method, avapor deposition method, or the like. As a material for the electrode, aconductive high molecular weight compound or the like may be used, inaddition to a metal and a metal compound.

A droplet discharge method is a method which can form a patternselectively, and a method for forming a conductive film by selectivelydischarging (jetting) a droplet (also referred to as a dot) of acomposition mixed with a material for a conductive film, an insulatingfilm or the like. A droplet discharge method is also referred to as anink-jetting method, depending on the system.

In the case where the conductive film is formed by using a dropletdischarge method, a conductive material mixed with a solvent describedhereinafter can be used: an element selected from the group consistingof gold (Au), silver (Ag), copper (Cu), platinum (Pt), palladium (Pd),tungsten (W), nickel (Ni), tantalum (Ta), bismuth (Bi), lead (Pb),indium (In), tin (Sn), zinc (Zn), titanium (Ti), or aluminum (Al), analloy or a dispersion nanoparticle including at least one of theelements, or a fine particle of silver halide.

Moreover, in the case where the conductive film is formed by using ascreen printing method or the like, a conductive paste in used. As theconductive paste, a conductive carbon paste, a conductive silver paste,a conductive copper paste, a conductive nickel, or the like can be used.After forming the conductive film in a predetermined pattern by theconductive paste, leveling and drying are carried out, and may be curedat temperatures of from 100 to 200° C.

After forming the gate electrode 101, an insulating film 102(hereinafter, a gate insulating film) which serves as a gate insulatingfilm is formed. Note that a TFT in this embodiment mode is describedusing an example in which the gate insulating film 102 is formed bydepositing SiON by using a CVD method; however, the gate insulating film102 may be formed by using a sputtering method, a spin coating method, avapor deposition method or the like, in addition to a CVD method.

As a material for the gate insulating film 102, an organic or inorganicmaterial such as silicon nitride oxide (SiON), silicon oxide (SiO₂),silicon nitride (SiN), siloxane, polysilazane, and polyvinyl alcohol,may be used. Siloxane is a material which has a skeleton constructedfrom the bond of silicon (Si) and oxygen (O), and is formed by using apolymer material as a starting material, which has a substituentincluding at least hydrogen or which has at least one selected from thegroup consisting of substituent including fluorine, alkyl group, andaromatic hydrocarbon group as a starting material. Polysilazane isformed by using a liquid material which includes a polymer materialhaving the bond of silicon (Si) and nitride (Ni), a so-calledpolysilazane, as a starting material.

In addition, an insulating film obtained by anodizing the gate electrodemay be used for an insulating film which is used as the gate insulatingfilm 102.

Next, a conductive film 103 (hereinafter, a source electrode and a drainelectrode) which serves as a source electrode and a drain electrode of aTFT is formed over the gate insulating film 102. Note that a TFT in thisembodiment mode is described using an example in which tungsten isformed as the source electrode and the drain electrode 103 by using asputtering method; however, the source electrode and the drain electrode103 may be formed by using an ink-jetting method, a spin coating method,a vapor deposition method or the like, in addition to a sputteringmethod. As a material for the source electrode and the drain electrode103, a conductive high molecular weight material or the like may beused, in addition to a metal and a metal compound. In other words, thesource electrode and the drain electrode 103 can be formed withreference to the material or the manufacturing method of the gateelectrode 101.

However, the source electrode and the drain electrode 103 need to forman ohmic contact with an organic semiconductor film. Therefore, in thecase where an organic semiconductor material is p-type, it is preferablyto use a material having a higher work function than an ionizationpotential of an organic semiconductor material, and in the case where anorganic semiconductor material is n-type, it is preferably to use amaterial having a lower work function than an ionization potential of anorganic semiconductor material. In this embodiment mode, pentacene whichis a p-type organic semiconductor material is used, so tungsten havingcomparatively a high work function is used.

Next, an organic semiconductor film 104 is formed over the insulatingfilm 102, source electrode 103, and drain electrode 103. Note that inthis embodiment mode, an example in which pentacene is used as anorganic semiconductor material is described, but as the organicsemiconductor material, an organic molecular crystal or an organic highmolecular weight compound may be used. As a specific organic molecularcrystal, a polycyclic aromatic compound, a conjugated double bond systemcompound, carotene, a macrocyclic compound and a complex thereof,phthalocyanine, diphenyl-pycrylhydrazyl, a charge transfer type complex(a. CT complex), a dye, a protein or the like can be given. For example,anthracene, tetracene, pentacene, 6T (hexathiophene), TCNQ(tetracyanoquinodimethane), a perylenetetracarboxylic derivative such asPTCDA, a naphthalene tetracarboxylic derivative such as NTCDA, or thelike can be given. On the other hand, as a specific organic highmolecular weight compound material, a p-conjugated polymer, a carbonnanotube, polyvinilpyridine, a phthalocyanine metal complex, aphthalocyanine metal complex, iodide complex or the like can be given.Specially, it is preferable to use a p-conjugated polymer having askeleton constituted by a conjugated double bond such as polyacetyrene,polyaniline, polypyrrole, polythienylene, polythiophene derivatives,poly (3-alkylthiophene), polyparaphenylene derivatives, orpolyparaphenylene vinylene derivatives.

As a method for forming a film, a method which can form a film having aneven film thickness may be employed. As a specific method, a vapordeposition method, a spin coating method, a bar-code method, a solutioncast method, a dipping method, or the like may be employed.

As pretreatment for forming an organic semiconductor film, plasmatreatment may be performed to a surface to be formed, or a film, forexample a self-assembled monolayer (SAM) and an alignment film, may beformed to enhance adhesion strength or the condition of the interface.

Note that in this embodiment mode, pentacene which is an organicmaterial is scattered by a vacuum vapor deposition method to form theorganic semiconductor film 104 over the gate insulating film 102 and thesource and drain electrodes 103.

Next, the element substrate 110 is baked after forming the organicsemiconductor film 104. At this time, the temperature is set to be lessthan the temperature in which the organic semiconductor film 104 isevaporated or decomposed. A temperature as high as possible within therange is effective for improving organic TFT characteristic. Inaddition, the temperature at this time is desirably the melting point ofthe organic semiconductor film 104 or less. As one of the causes ofimproving the TFT characteristic by performing baking, it is speculatedthat carrier transportability is improved since the adhesion strengthbetween the organic semiconductor film 104, and the source electrode anddrain electrode 103 and the insulating film 102 is enhanced by baking;and therefore, an injection barrier becomes decreased. Moreover, it isspeculated that a high temperature is effective for improving TFTcharacteristic to enhance the adhesion strength between the organicsemiconductor film 104, and the source electrode and drain electrode 103and the insulating film 102. Furthermore, it is speculated that the TFTcharacteristic is improved compared with before baking since moisture inthe organic semiconductor film 104 is decreased by performing baking;and therefore, the deterioration of the organic semiconductor film 104can be suppressed.

With reference to a result of before and after baking using pentacene asan organic semiconductor material as shown in embodiment 6, thetemperature during baking is preferably set at a temperature in whichgrain boundary (grain) of pentacene does not grow before and afterbaking.

With reference to a result of baking under atmospheric pressure usingpentacene as an organic semiconductor material as shown in embodiment 1,the shift of a threshold value becomes smaller as a temperature becomesgradually high to 120° C., 150° C. and 200° C. In other words, it isunderstood that a high temperature is effective for improving theorganic TFT characteristic. Moreover, according to embodiment 1, in thecase where pentacene is used as the organic semiconductor material, itis understood that a temperature of approximately 250° C. is thetemperature of being evaporated or decomposed. Therefore, heatingtemperature is preferably less than 250° C. It is speculated that theTFT characteristic is improved since carrier transportability isimproved by enhancing the adhesion strength between the organicsemiconductor film 104 and the source electrode and the drain electrode103 and the insulating film 102 by performing baking; and therefore, aninjection barrier becomes small. Moreover, it is speculated that ahigher temperature is furthermore effective for improving the TFTcharacteristic, since the adhesion strength between the organicsemiconductor film 104 and the source electrode and the drain electrode103 and the insulating film 102 is enhanced. It is also speculated thatthe TFT characteristic is improved compared with before baking sincemoisture in the organic semiconductor film 104 is decreased byperforming baking; and therefore, the deterioration of the organicsemiconductor film 104 can be suppressed.

As for the atmosphere during baking, inert gas atmosphere such asnitrogen or argon may be employed in consideration of deterioration ofthe organic semiconductor film due to oxygen or moisture, even though aneffect can be also expected in atmospheric air. Moreover, the baking maybe also carried out under reduced pressure (for example, from 1.3*10⁻³Pa to 6.7*10⁴ Pa) to suppress a deterioration of the organicsemiconductor film and make baking temperature low.

With reference to a result of baking under reduced pressure (1.2*10⁴ Pa)using pentacene as an organic semiconductor material as shown inembodiment 3, the baking performed under reduced pressure may be moreeffective compared with the baking under atmospheric pressure, in thecase where the baking is carried out at same temperature (120° C. and150° C.). Moreover, it is understood that the effect of the baking canbe obtained at a lower temperature by carrying out the baking underreduced pressure. It is speculated that a TFT characteristic is improvedby performing baking under reduced pressure, since deterioration such asoxidation of the organic semiconductor film due to oxygen in atmosphericair is suppressed.

In addition, the baking may be carried out under atmospheric pressure orunder reduced pressure after being left under atmospheric pressure afterdeposition. In addition, reduced pressure may be kept after depositionto carry out the baking. In other words, the organic semiconductor filmmay be heated in a processing chamber in which the organic semiconductorfilm is formed.

Embodiment 4 shows a result of baking which is carried out under reducedpressure after once being left under atmospheric pressure is shown, andEmbodiment 5 shows a result of baking which is carried out under reducedpressure after deposition. It is understood that an effect of the bakingis obtained in the both cases.

Furthermore, it is understood according to embodiment 4 that an organicTFT characteristic is recovered by performing baking after once beingleft under atmospheric pressure.

As described above, according to the present invention, it is understoodthat an organic TFT characteristic is improved by performing bakingafter an organic semiconductor film is formed. It is speculated that theTFT characteristic is improved since moisture in the organicsemiconductor film is reduced by performing baking; and therefore, adeterioration of the organic semiconductor film is suppressed. It isalso speculated that the adhesion strength between the electrode and theinsulating film, and the organic semiconductor film is enhanced bybaking, and the crystallinity of the organic semiconductor film andcarrier transportability are improved; therefore, the TFTcharacteristics are improved compared with before baking. As for thebaking under reduced pressure, it is speculated that the TFTcharacteristic is improved since a deterioration of the organicsemiconductor film due to oxygen in atmospheric air is suppressed.

Thus, an organic TFT of bottom contact type is completed.

The organic TFT described above can be utilized as a switching elementof a liquid crystal display device. For example, a liquid crystaldisplay device can be manufactured by forming a pixel electrode (ITO ora metal film) over either a source electrode or a drain electrode and byproviding with a liquid crystal layer. Moreover, an organic TFTaccording to the present invention may be utilized for such as aswitching element of a display device having a light emitting element orthe like.

Embodiment Mode 2

In this embodiment mode, an organic TFT of top contact type in which asource electrode and a drain electrode are formed after forming anorganic semiconductor film, which is different from Embodiment Mode 1,is described with reference to FIG. 2.

First, as in Embodiment Mode 1, an element substrate 210 in which a gateelectrode 201 is formed over a substrate 200 and a gate insulating film202 provided to cover the gate electrode is formed is prepared. Amaterial of the gate electrode and the gate insulating film or a methodfor manufacturing thereof can be referred to Embodiment Mode 1.

Next, an organic semiconductor film 203 is formed over the elementsubstrate 210. As the organic semiconductor material, an organicmolecular crystal or an organic high molecular weight compound may beused. As a specific organic molecular crystal, a polycyclic aromaticcompound, a conjugated double bond system compound, carotene, amacrocyclic compound and a complex thereof, phthalocyanine,diphenyl-pycrylhydrazyl, a charge transfer type complex (a CT complex),a dye, a protein or the like can be given. For example, anthracene,tetracene, pentacene, 6T (hexathiophene), TCNQ(tetracyanoquinodimethane), a perylenetetracarboxylic derivative such asPTCDA, a naphthalene tetracarboxylic derivative such as NTCDA, or thelike can be given. On the other hand, as a specific organic highmolecular weight compound material, a p-conjugated polymer, a carbonnanotube, polyvinilpyridine, a phthalocyanine metal complex, aphthalocyanine metal complex, iodide complex or the like can be given.Specially, it is preferable to use a p-conjugated polymer having askeleton constituted by a conjugated double bond such as polyacetyrene,polyaniline, polypyrrole, polythienylene, polythiophene derivatives,poly (3-alkylthiophene), polyparaphenylene derivatives, orpolyparaphenylene vinylene derivatives.

Moreover, as a method for forming a film, a method in which a filmhaving an even film thickness can be formed over the element substrate210 may be employed. As a specific method, a vapor deposition method, aspin coating method, a bar-code method, a solution cast method, adipping method, or the like may be employed.

As pretreatment for forming an organic semiconductor film 203, plasmatreatment may be performed to a surface to be formed, or a film toenhance adhesion strength or condition of the interface for example aself-assembled monolayer (SAM) and an alignment film may be formed.

Subsequently, an electrode that serves as a source electrode 204 and adrain electrode 204 of the TFT are formed. A material of the sourceelectrode 204 and the drain electrode 204 may refer to Embodiment Mode1.

The source electrode 204 and the drain electrode 204 need to form ohmiccontact to with an organic semiconductor film 203. Therefore, in thecase where an organic semiconductor material is p-type, it is preferableto use a material having a higher work function than ionizationpotential of an organic semiconductor material, and in the case where anorganic semiconductor material is n-type, it is preferable to use amaterial having a lower work function than ionization potential of anorganic semiconductor material. In addition, as a method for forming afilm, a method which can form a film having an even film thickness overthe element substrate 210 may be employed. A specific method may referto Embodiment Mode 1.

Next, the element substrate 210 is baked after forming the sourceelectrode 204 and the drain electrode 204. At this time, a temperatureis set to be less than the temperature in which the organicsemiconductor film is evaporated or decomposed. Moreover, a temperaturewhich is as high as possible within the range of the melting point orless is effective for improving the organic TFT characteristic.Moreover, baking may be performed before forming the source electrode204 and the drain electrode 204 and after forming the organicsemiconductor film 203.

As for the atmosphere during the baking, inert gas atmosphere such asnitrogen or argon may be employed in consideration of deterioration ofthe organic semiconductor film due to oxygen or moisture, even though aneffect can be also expected when baking is performed under atmosphericpressure. Moreover, the baking may be carried out under reduced pressure(for example, from 1.3*10⁻³ Pa to 6.7*10⁴ Pa) to suppress adeterioration of the organic semiconductor film and make bakingtemperature lower, as described above.

Thus, an organic TFT of top contact type is completed.

The organic TFT described above can be utilized as a switching elementof a liquid crystal display device. For example, a liquid crystaldisplay device can be manufactured by forming a pixel electrode (ITO ora metal film) on either a source electrode or a drain electrode and byproviding with a liquid crystal layer. Moreover, an organic TFTaccording to the invention may be utilized for such a switching elementof a display device having a light emitting element and the like.

Embodiment 1

In this embodiment, a result which is temperature dependence of electricproperties of the organic TFT manufactured by performing baking underatmospheric pressure according to the above-mentioned Embodiment Mode 1is shown. Note that the organic TFT used as a test sample has astructure in which a gate electrode 301 formed by tungsten is providedover a quartz substrate, a gate insulating film is provided over thegate electrode 301, a source electrode 302 and a drain electrode 303formed by tungsten are provided over the gate insulating film, and anorganic semiconductor film is provided between the source electrode 302and the drain electrode 303, in atmospheric air as shown FIG. 3.Moreover, the source electrode 302, the drain electrode 303 and the gateelectrode 301 is each provided with a measuring pad (a pad 304 for thesource electrode, a pad 305 for the drain electrode, a pad 306 for thegate electrode) to apply measurement voltage or to detect current.

In addition, a channel length of the organic TFT corresponds to thelength between the source electrode and the drain electrode (referred toas L in FIG. 3), and the value of L is 5 μm. On the other hand, achannel width of the organic TFT corresponds to the length of the regionwhere the source electrode and the drain electrode are overlapped witheach other (referred to as W in FIG. 3), and the value of W is 8000 μm.

Pentacene was used as a material for the organic semiconductor, and theorganic semiconductor was formed to be 50 nm thick. As a film formationmethod, a vapor deposition method was used.

The baking condition after deposition is as follows:

-   -   (1) Not baked    -   (2) Baked for 10 minutes at a temperature of 120° C. under        atmospheric pressure    -   (3) Baked for 10 minutes at a temperature of 150° C. under        atmospheric pressure    -   (4) Baked for 10 minutes at a temperature of 200° C. under        atmospheric pressure    -   (5) Baked for 10 minutes at a temperature of 250° C. under        atmospheric pressure

FIG. 4 shows a result of Vg-Id characteristic in which the current ofthe drain electrode and a gate voltage are detected when voltage of −10Vis applied as Vd in the baking condition (1) through (5).

FIG. 4 shows that a threshold value of ON-OFF approaches 0V byperforming baking after deposition. Under atmospheric pressure, athreshold value in the case where baking is carried out for 10 minutesat a temperature of 150° C. (3) shifts significantly than a thresholdvalue in the case where baking is carried out for 10 minutes at atemperature of 120° C. (2). On the other hand, the case of 150° C. (3)and 200° C. (4) has few differences. FIG. 4 also shows that leakagecurrent at OFF is decreased by performing baking after deposition. It isalso understood that the case of 10 minutes at 150° C. (3) shifts morecompared with the case of 10 minutes at 120° C. (2), and the case of 10minutes at 200° C. (4) shifts more compared with the case of 10 minutesat 150° C. (3). Accordingly, it is speculated that the TFTcharacteristic is improved compared with before baking since moisture inthe organic semiconductor film is decreased by performing baking; andtherefore, the deterioration of the organic semiconductor film can besuppressed. It is also speculated that the adhesion strength between theelectrode and the insulating film, and the organic semiconductor film isenhanced by baking, and the crystallinity of the organic semiconductorfilm and carrier transportability are improved; therefore, the TFTcharacteristic is improved compared with before performing baking.Furthermore, it is speculated that high temperature is effective forimproving the TFT characteristic to enhance the adhesion strengthbetween the organic material and both the source and drain electrodes304 and the insulating film.

As described above, it can be understood that baking after deposition iseffective to improve the organic TFT characteristic.

In addition, it seems that there is no improvement of the organic TFTcharacteristic in the case where baking is carried out at a temperatureof 250° C. for 10 minutes (5). It can be considered that the organic TFTcharacteristic is disappeared due to thermal decomposition oroxidization of pentacene at a temperature of approximately 250° C.Therefore, it is understood that heat temperature is preferably set tobe less than 250° C. in the case where pentacene is used as a materialfor the organic semiconductor material.

Embodiment 2

In this embodiment, a result which is time dependence of electricproperties of the organic TFT manufactured by performing baking underatmospheric pressure according to the above-mentioned Embodiment Mode 1is shown. Note that a manufacturing condition of the organic TFT, otherthan the baking condition after deposition, used as a test sample is thesame as in Embodiment 1.

The baking condition after deposition is as follows:

-   -   (1) Before baking after deposition    -   (2) Baking (1) at a temperature of 120° C. for 10 minutes under        atmospheric pressure    -   (3) Baking (2) at a temperature of 120° C. for 30 minutes under        atmospheric pressure

FIG. 5 shows a result of Vg-Id characteristic in which the current ofthe drain electrode and gate voltage are detected when voltage of −10Vis applied as Vd in the baking condition (1) through (3).

FIG. 5 shows that a threshold value of ON-OFF approaches 0V byperforming baking after deposition, and shifts significantly when thebaking time is long. Accordingly, it is speculated that the TFTcharacteristic is improved compared with before baking since moisture inthe organic semiconductor film is decreased by performing baking; andtherefore, the deterioration of the organic semiconductor film can besuppressed. It is also speculated that the adhesion strength between theelectrode and the insulating film, and the organic semiconductor film isenhanced by baking, and the crystallinity of the organic semiconductorfilm and carrier transportability are improved; therefore, the TFTcharacteristic is improved compared with before performing baking.Furthermore, it is speculated that reducing of moisture in the organicsemiconductor film and enhancing the adhesion strength between theorganic semiconductor film and both of the source and drain electrodesand the insulating film are promoted by performing baking for a longtime, and thus it is effective for improving characteristic of theorganic semiconductor.

Accordingly, it is understood that baking after deposition is effectiveto improve the organic TFT characteristic.

Embodiment 3

In this embodiment, a result which is temperature dependence of electricproperties of the organic TFT manufactured by performing baking underreduced pressure (1.2*10⁴ Pa) after once being left under atmosphericpressure after deposition according to the above-mentioned EmbodimentMode 1 is shown. Note that a manufacturing condition of the organic TFTused as a test sample is the same as in Embodiment 1, other than thebaking condition after deposition.

The baking condition is as follows:

-   -   (1) Baked for 10 minutes at a temperature of 120° C. under        reduced pressure (1.2*10⁴ Pa)    -   (2) Baked for 10 minutes at a temperature of 150° C. under        reduced pressure (1.2*10⁴ Pa)    -   (3) Baked for 10 minutes at a temperature of 200° C. under        reduced pressure (1.2*10⁴ Pa)

FIG. 6 shows a result of Vg-Id characteristic in which the current ofthe drain electrode and gate voltage are detected when voltage of −10Vis applied as Vd in the baking condition (1) through (3).

FIG. 6 shows that a threshold value of ON-OFF approaches 0V byperforming baking after deposition. Under reduced pressure (1.2*10⁴ Pa),a threshold value in the case where baking is carried out for 10 minutesat a temperature of 150° C. (2) shifts significantly than a thresholdvalue in the case where baking is carried out for 10 minutes at atemperature of 120° C. (1). FIG. 6 also shows that leakage current atOFF is decreased by performing baking after deposition. From seeing thedecrease, it is also shown that the case of 10 minutes and 150° C. (2)shifts more than the case of 10 minutes and 120° C. (1). Furthermore, itcan be understood that a preferable S value (subthreshold value) isobtained, since the beginning of a slope is steeper than the case wherebaking is carried out under atmospheric pressure according to theEmbodiment 1. Accordingly, as well as in Embodiment 1, it is speculatedthat the TFT characteristic is improved compared with before bakingsince moisture in the organic semiconductor film is decreased byperforming baking; and therefore, the deterioration of the organicsemiconductor film can be suppressed. It is also speculated that theadhesion strength between the source and drain electrodes and theinsulating film, and the organic semiconductor film is enhanced bybaking, and the crystallinity of the organic semiconductor film andcarrier transportability are improved; therefore, the TFT characteristicis improved compared with before performing baking. Furthermore, it isspeculated that a higher temperature is more effective to improve theTFT characteristic since the adhesion strength between the organicmaterial and both the source and drain electrodes and the insulatingfilm is improved. In addition, it is speculated that high temperaturegives high effect for improving the TFT characteristic to enhance theadhesion strength between the organic material and both the electrodesand the insulating film. Moreover, in this embodiment, it is speculatedthat the TFT characteristic is improved by performing baking underreduced pressure since the deterioration such as oxidation of theorganic semiconductor film due to oxygen in atmospheric air issuppressed, compared with the baking under atmospheric pressure.

Accordingly, it can be understood that baking after deposition iseffective to improve the organic TFT characteristic. Further, whenbaking is performed under reduced pressure, baking temperature can bemade lower.

Embodiment 4

According to the above-mentioned Embodiment Mode 1, a change over timein electric properties due to being left under atmospheric pressure ofan organic TFT, which is manufactured by performing baking under reducedpressure (1.2*10⁴ Pa) after once being left under atmospheric air afterdeposition was evaluated in this embodiment. The effect of subsequentbaking under reduced pressure (1.2*10⁴ Pa) is also evaluated in thisembodiment mode. Hereinafter, the results are shown. Note that amanufacturing condition of the organic TFT used as a test sample, otherthan the baking condition after deposition, is the same as in Embodiment1.

The baking condition is as follows:

-   -   (1) Baking for 30 minutes at a temperature of 150° C. under        reduced pressure (1.2*10⁴ Pa)    -   (2) Being left (1) for 48 hours under atmospheric air    -   (3) Baking (2) for 30 minutes at a temperature of 150° C. under        reduced pressure (1.2*10⁴ Pa)

FIG. 7 shows a result of the Vg-Id characteristic in which the currentof the drain electrode and a gate voltage are detected when voltage of−10V is applied as Vd in the baking condition (1) through (3).

FIG. 7 shows that a threshold value of ON-OFF approaches 0V byperforming baking after deposition (1), and the ON current is decreasedby being left for 48 hours under atmospheric air (2); and thus the TFTcharacteristic is deteriorated. FIG. 7 also shows that the ON current isincreased by performing baking again thereafter (3); and thus theorganic TFT characteristic is improved. As well as in Embodiment 4, itis speculated that the TFT characteristic is improved since moisture inthe organic semiconductor film is reduced by performing baking; andtherefore, the deterioration of the organic semiconductor film issuppressed. It is also speculated that the adhesion strength between thesource and drain electrodes and the insulating film, and the organicsemiconductor film is enhanced by baking, and the crystallinity of theorganic semiconductor film and carrier transportability are improved;therefore, the TFT characteristic is improved compared with beforeperforming baking. Furthermore, it is speculated that the TFTcharacteristic is improved since the deterioration such as oxidation ofthe organic semiconductor film due to oxygen in atmospheric air issuppressed by performing baking under reduced pressure.

Accordingly, it can be understood that baking after deposition iseffective to recover the deterioration of the organic TFT characteristicby being left under atmospheric pressure.

Embodiment 5

In this embodiment, a result which is electric properties of an organicTFT manufactured by performing baking in a deposition chamberimmediately after deposition according to the above-mentioned EmbodimentMode 1 is shown. Note that a manufacturing condition of the organic TFTused as a test sample, other than the baking condition after deposition,is the same as in Embodiment 1.

As for the baking condition after deposition, baking was carried outunder reduced pressure (1.3*10⁻³ Pa) that is the same at the time ofdepositing, since the baking is carried out in the deposition chamber.The baking condition is as follows:

-   -   (1) Not baked    -   (2) Baked at a temperature of 120° C. for 10 minutes

FIG. 8 shows a result in which the Vg-Id characteristic in which thecurrent of the drain electrode and the gate voltage are detected when avoltage of −10V is applied as Vd in the baking condition (1) and (2).

FIG. 8 shows that a threshold value of ON-OFF approaches 0V byperforming baking after deposition in the deposition chamber; and thusthe TFT characteristic is improved. It is speculated that the TFTcharacteristic is improved compared with before baking since moisture inthe organic semiconductor film is decreased by performing baking; andtherefore, the deterioration of the organic semiconductor film can besuppressed. It is also speculated that the adhesion strength between thesource and drain electrodes and the insulating film, and the organicsemiconductor film is enhanced by baking, and the crystallinity of theorganic semiconductor film and carrier transportability are improved;therefore, the TFT characteristic is improved compared with beforeperforming baking.

Accordingly, it can be understood that baking after deposition in thedeposition chamber is effective to improve the organic TFTcharacteristic.

Embodiment 6

In this embodiment, a result in which a change of the grain boundary(grain) of pentacene and film thickness of an organic layer byperforming baking after deposition are detected with AFM is shown. Notethat as for a test sample, pentacene was deposited to have a filmthickness of 50 nm over a substrate that is the same as in Embodiment 1.As for a film formation method, a vapor deposition method was employed.

The condition of the test portion is as follows:

-   -   (1) Not baked after deposition    -   (2) Baked at a temperature of 150° C. for 10 minutes under        reduced pressure (1.2*10⁴ Pa) after deposition

FIG. 9 shows a measurement result with AFM according to the condition(1), and FIG. 10 shows a measurement result with AFM according to thecondition (2).

FIGS. 9 and 10 show that the grain boundary (grain) size of pentacenedoes not change whether baking is carried out after deposition or not.In addition, the film thickness of the organic film does not change atthis time.

According to the above-mentioned results, it is understood that apreferable heating temperature after the organic semiconductor film isformed is a temperature in which crystal growth does not happen in theorganic semiconductor, preferably, a temperature in which average valueof the growth of grain boundary (grain) size of the organicsemiconductor film is not 10% or more.

Embodiment Mode 3

A mode of a liquid crystal device including the semiconductor deviceaccording to the present invention is described with reference to FIG.11. Note that a structure of the liquid crystal device is not limited inparticular, and for example, a liquid crystal device in which a drivecircuit is provided for an element substrate may be preferable, inaddition to the mode shown in this embodiment mode. Moreover, thisembodiment is not limited to the liquid crystal, and an organicsemiconductor device according to the invention may be employed for aswitching element and the like of a display device having a lightemitting element.

FIG. 11 is a top view for schematically showing a liquid crystal device.The liquid crystal device according to this embodiment has a structurein which an element substrate 1101 is attached to an opposing substrate1102 so as to face each other. The liquid crystal device according tothis embodiment includes a pixel portion 1103. A terminal portion 1104provided along one edge of the pixel portion 1103 is provided with aflexible printed circuit (FPC) 1105, and a signal is inputted from adrive circuit to the pixel portion 1103 via the flexible printed circuit1105. Note that the drive circuit and the flexible printed circuit maybe provided separately, or may be provided in complex with each othersuch as TCP in which an IC chip is mounted over the FPC in which awiring pattern is formed.

As for the pixel portion 1103, there is no limitation in particular. Forexample, the pixel portion 1103 includes a liquid crystal element and atransistor for driving the liquid crystal element, as shown in across-sectional view of FIG. 12A or FIG. 12B. FIG. 12A and FIG. 12B eachshow a mode of a cross-sectional structure of the liquid crystal device,and each of them has a different transistor structure.

The liquid crystal device shown in a cross-sectional view of FIG. 12Aincludes an element substrate 521 provided with a transistor 527 havingelectrodes 525 and 526 which serves as a source electrode or a drainelectrode over an organic semiconductor film 524.

Moreover, a liquid crystal layer 534 is sandwiched between a pixelelectrode 529 and an opposing electrode 532. As a material for the pixelelectrode 529 and the opposing electrode 532, a light transparentmaterial such as indium tin oxide (ITO) or indium tin oxide includingsilicon oxide may be used.

Furthermore, orientation films 530 and 533 are provided for the surfacesides of the pixel electrode 529 and the opposing electrode 532, whichare to be in contact with the liquid crystal layer 534. A spacer 535 isdispersed in the liquid crystal layer to keep a cell gap.

A transistor 527 is covered with an insulating layer 528 in which acontact hole is provided, and the electrode 526 is electricallyconnected to the pixel electrode 529. The insulating layer 528 may beformed by sputtering or chemical vapor deposition (CVD) using teflon.Moreover, thermal CVD using silicon nitride, silicon oxide siliconnitride oxide or the like may be performed to suppress a deteriorationof the organic semiconductor film 524.

The opposing electrode 532 is supported by an opposing substrate 531.The organic semiconductor film 524 is overlapped with a gate electrode522 with a gate insulating layer 523 therebetween.

In addition, a liquid crystal device shown in a cross-sectional view ofFIG. 12B includes an element substrate 551 provided with a transistor557 having a structure in which at least a portion of electrodes 555 and554 which serves as a source electrode or a drain electrode is coveredwith an organic semiconductor film 556. Moreover, a liquid crystal layer564 is sandwiched between a pixel electrode 559 and an opposingelectrode 562. Orientation films 560 and 563 are provided for thesurface sides of the pixel electrode 559 and the opposing electrode 562,which are to be in contact with the liquid crystal layer 564. A spacer565 is dispersed in the liquid crystal layer to keep a cell gap.

A transistor 557 is covered with insulating layers 558 a and 558 b inwhich a contact hole is provided, and the electrode 554 is electricallyconnected to the pixel electrode 559. Note that an insulating layerwhich covers the transistor 557 may be a laminated layer formed by theinsulating layer 558 a and the insulating layer 558 b as shown in FIG.12B, or may be a single layer formed by the insulating layer 528 asshown in FIG. 12A. In addition, an insulating layer which covers thetransistor 557 may be a layer having a planarized surface like theinsulating layer 558 b. The insulating layer 558 a may be formed as sameas the insulating film 528 described above. The insulating film 528 bmay be formed by spin carting using an organic compound such as acryl,polyimide, or polyimideamide. In addition, a positive type or negativetype photosensitive material may be used.

The opposing electrode 561 is supported by an opposing substrate 562.Moreover, the organic semiconductor film 556 is overlapped with a gateelectrode 552 with a gate insulating layer 553 therebetween.

Embodiment Mode 4

The display device as described above can be used as a display devicemounted to a cellular phone, a TV receiver and the like as shown inFIGS. 13A to 13C. Moreover, the display device may be mounted to a card,for example an ID card, which serves to manage personal information.

FIG. 13A shows a view of a cellular phone, which includes a main body1302 includes a display portion 1301, an audio output portion 1304, anaudio input portion 1305, operation keys 1306 and 1307, an antenna 1303,and the like. The cellular phone has high operating characteristic andhigh reliability. Such a cellular phone can be completed byincorporating the organic semiconductor device of the present inventioninto the display portion 1301.

FIG. 13B shows a TV receiver manufactured by applying the presentinvention, which includes a display portion 1311, a casing 1312,speakers 1313, and the like. The TV receiver has high operatingcharacteristic and high reliability. Such a TV receiver can be completedby incorporating the organic semiconductor device of the invention intothe display portion 1311.

FIG. 13C shows an ID card manufactured by applying the invention, whichincludes a support 1321, a display portion 1322, an integrated circuitchip 1323 incorporated in the support 1321, and the like. Note thatintegrated circuits 1324 and 1325 which drive the display portion 1322are also incorporated in the support 1321. The ID card has highreliability. Moreover, for example in the display portion 1322, the IDcard can display information inputted and outputted in the integratedcircuit chip 1323; and thus, what kind of information is inputted andoutputted can be confirmed. Such an ID card can be completed byincorporating the organic semiconductor device according to theinvention in the display portion 1322.

This application is based on Japanese Patent Application serial no.2003-434620 field in Japan Patent Office on Dec. 26, 2003, the contentsof which are hereby incorporated by reference.

1. A method for manufacturing an organic semiconductor element,comprising the steps of: forming an organic semiconductor film; andheating the organic semiconductor film under atmospheric pressure orunder reduced pressure.
 2. A method for manufacturing an organicsemiconductor element, comprising the steps of: forming a gateelectrode; forming an organic semiconductor film over the gateelectrode; heating the organic semiconductor film under atmosphericpressure or under reduced pressure; and forming a source electrode and adrain electrode over the organic semiconductor film which is heated. 3.A method for manufacturing an organic semiconductor element, comprisingthe steps of: forming a gate electrode; forming a source electrode or adrain electrode over the gate electrode; forming an organicsemiconductor film over the source electrode and the drain electrode;and heating the organic semiconductor film under atmospheric pressure orunder reduced pressure.
 4. A method for manufacturing an organicsemiconductor element, comprising the steps of: forming an organicsemiconductor film to be in contact with an inorganic film; and heatingthe organic semiconductor film under atmospheric pressure or underreduced pressure.
 5. A method for manufacturing an organic semiconductorelement, comprising the steps of: forming an organic semiconductor filmto be in contact with a gate insulating film; and heating the organicsemiconductor film under atmospheric pressure or under reduced pressure.6. The method for manufacturing an organic semiconductor elementaccording to claim 1, wherein the organic semiconductor film is heatedin an inert gas atmosphere.
 7. The method for manufacturing an organicsemiconductor element according to claim 2, wherein the organicsemiconductor film is heated in an inert gas atmosphere.
 8. The methodfor manufacturing an organic semiconductor element according to claim 3,wherein the organic semiconductor film is heated in an inert gasatmosphere.
 9. The method for manufacturing an organic semiconductorelement according to claim 4, wherein the organic semiconductor film isheated in an inert gas atmosphere.
 10. The method for manufacturing anorganic semiconductor element according to claim 5, wherein the organicsemiconductor film is heated in an inert gas atmosphere.
 11. The methodfor manufacturing an organic semiconductor element according to claim 1,wherein the organic semiconductor film is heated at a temperature whichis less than the melting point of the organic semiconductor film. 12.The method for manufacturing an organic semiconductor element accordingto claim 2, wherein the organic semiconductor film is heated at atemperature which is less than the melting point of the organicsemiconductor film.
 13. The method for manufacturing an organicsemiconductor element according to claim 3, wherein the organicsemiconductor film is heated at a temperature which is less than themelting point of the organic semiconductor film.
 14. The method formanufacturing an organic semiconductor element according to claim 4,wherein the organic semiconductor film is heated at a temperature whichis less than the melting point of the organic semiconductor film. 15.The method for manufacturing an organic semiconductor element accordingto claim 5, wherein the organic semiconductor film is heated at atemperature which is less than the melting point of the organicsemiconductor film.
 16. The method for manufacturing an organicsemiconductor element according to claim 1, wherein the organicsemiconductor film is heated at a temperature of less than 250° C. 17.The method for manufacturing an organic semiconductor element accordingto claim 2, wherein the organic semiconductor film is heated at atemperature of less than 250° C.
 18. The method for manufacturing anorganic semiconductor element according to claim 3, wherein the organicsemiconductor film is heated at a temperature of less than 250° C. 19.The method for manufacturing an organic semiconductor element accordingto claim 4, wherein the organic semiconductor film is heated at atemperature of less than 250° C.
 20. The method for manufacturing anorganic semiconductor element according to claim 5, wherein the organicsemiconductor film is heated at a temperature of less than 250° C. 21.The method for manufacturing an organic semiconductor element accordingto claim 1, wherein the organic semiconductor film is heated at atemperature in which average value of the grain size of the organicsemiconductor film does not grow 10% or more.
 22. The method formanufacturing an organic semiconductor element according to claim 2,wherein the organic semiconductor film is heated at a temperature inwhich average value of the grain size of the organic semiconductor filmdoes not grow 10% or more.
 23. The method for manufacturing an organicsemiconductor element according to claim 3, wherein the organicsemiconductor film is heated at a temperature in which average value ofthe grain size of the organic semiconductor film does not grow 10% ormore.
 24. The method for manufacturing an organic semiconductor elementaccording to claim 4, wherein the organic semiconductor film is heatedat a temperature in which average value of the grain size of the organicsemiconductor film does not grow 10% or more.
 25. The method formanufacturing an organic semiconductor element according to claim 5,wherein the organic semiconductor film is heated at a temperature inwhich average value of the grain size of the organic semiconductor filmdoes not grow 10% or more.
 26. The method for manufacturing an organicsemiconductor element according to claim 1, wherein the organicsemiconductor film is formed by depositing pentacene by using a vacuumvapor deposition method.
 27. The method for manufacturing an organicsemiconductor element according to claim 2, wherein the organicsemiconductor film is formed by depositing pentacene by using a vacuumvapor deposition method.
 28. The method for manufacturing an organicsemiconductor element according to claim 3, wherein the organicsemiconductor film is formed by depositing pentacene by using a vacuumvapor deposition method.
 29. The method for manufacturing an organicsemiconductor element according to claim 4, wherein the organicsemiconductor film is formed by depositing pentacene by using a vacuumvapor deposition method.
 30. The method for manufacturing an organicsemiconductor element according to claim 5, wherein the organicsemiconductor film is formed by depositing pentacene by using a vacuumvapor deposition method.
 31. The method for manufacturing an organicsemiconductor element according to claim 1, wherein the organicsemiconductor film is heated in a processing chamber in which theorganic semiconductor film is formed.
 32. The method for manufacturingan organic semiconductor element according to claim 2, wherein theorganic semiconductor film is heated in a processing chamber in whichthe organic semiconductor film is formed.
 33. The method formanufacturing an organic semiconductor element according to claim 3,wherein the organic semiconductor film is heated in a processing chamberin which the organic semiconductor film is formed.
 34. The method formanufacturing an organic semiconductor element according to claim 4,wherein the organic semiconductor film is heated in a processing chamberin which the organic semiconductor film is formed.
 35. The method formanufacturing an organic semiconductor element according to claim 5,wherein the organic semiconductor film is heated in a processing chamberin which the organic semiconductor film is formed.
 36. The method formanufacturing an organic semiconductor element according to claim 1,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a sputtering method, an ink-jetting method,a spin coating method, or a vapor deposition method.
 37. The method formanufacturing an organic semiconductor element according to claim 2,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a sputtering method, an ink-jetting method,a spin coating method, or a vapor deposition method.
 38. The method formanufacturing an organic semiconductor element according to claim 3,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a sputtering method, an ink-jetting method,a spin coating method, or a vapor deposition method.
 39. The method formanufacturing an organic semiconductor element according to claim 4,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a sputtering method, an ink-jetting method,a spin coating method, or a vapor deposition method.
 40. The method formanufacturing an organic semiconductor element according to claim 5,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a sputtering method, an ink-jetting method,a spin coating method, or a vapor deposition method.
 41. The method formanufacturing an organic semiconductor element according to claim 1,wherein the gate electrode or the source electrode and the drainelectrode is formed by using a conductive film having tungsten.
 42. Themethod for manufacturing an organic semiconductor element according toclaim 2, wherein the gate electrode or the source electrode and thedrain electrode is formed by using a conductive film having tungsten.43. The method for manufacturing an organic semiconductor elementaccording to claim 3, wherein the gate electrode or the source electrodeand the drain electrode is formed by using a conductive film havingtungsten.
 44. The method for manufacturing an organic semiconductorelement according to claim 4, wherein the gate electrode or the sourceelectrode and the drain electrode is formed by using a conductive filmhaving tungsten.
 45. The method for manufacturing an organicsemiconductor element according to claim 5, wherein the gate electrodeor the source electrode and the drain electrode is formed by using aconductive film having tungsten.
 46. The method for manufacturing anorganic semiconductor element according to claim 1, wherein the organicsemiconductor element is applied to an electronic apparatus selectedfrom the group consisting of a cellular phone, a TV receiver, and an IDcard.
 47. The method for manufacturing an organic semiconductor elementaccording to claim 2, wherein the organic semiconductor element isapplied to an electronic apparatus selected from the group consisting ofa cellular phone, a TV receiver, and an ID card.
 48. The method formanufacturing an organic semiconductor element according to claim 3,wherein the organic semiconductor element is applied to an electronicapparatus selected from the group consisting of a cellular phone, a TVreceiver, and an ID card.
 49. The method for manufacturing an organicsemiconductor element according to claim 4, wherein the organicsemiconductor element is applied to an electronic apparatus selectedfrom the group consisting of a cellular phone, a TV receiver, and an IDcard.
 50. The method for manufacturing an organic semiconductor elementaccording to claim 5, wherein the organic semiconductor element isapplied to an electronic apparatus selected from the group consisting ofa cellular phone, TV receiver, and an ID card.